Block Crack Options

[adf5565]

As part of my turbo build I performed an inspection of the lower end of my block. It turns out I have I believe 3 cracks in the main bearing webs. All 3 are facing the rear of the motor on the outer bolts, 1 is on the 3rd from the front (middle) web, while the other 2 are both on the 4th. None of the cracks appear to penetrate to the opposite side of the web.

I was originally planning on replacing the cap bolts and adding ARP main studs, but what would be the best course of action now? Still add the studs? Add the studs and a DSG girdle? Just the girdle? Or just leave as is and hope for the best?

Here are the pics of each of the cracks. One is more pronounced than the other two.

 

[porkysplace]

Find a different block to build .

 

[LT67]

Sometimes the cracks can be welded back together. Let a machine shop look at it...

 

[MarkM]

Those are just the cracks you can see. I would find another block and start fresh. Just my .02 cents.

Mark

 

[GopherHill]

Have a shop do a magnetic particle inspection or whatever is used these days.
Peace of mind before you junk the block..

 

[porkysplace]

Sometimes the cracks can be welded back together. Let a machine shop look at it...

A different block is probably cheaper than the cost of a questionable repair .

 

[87cr250r]

Lock-N-Stitch has a repair kit for these engines. You'll need to dye pen the cracks to evaluate the severity. I retired my 6.2 block because of this cracking. After sitting out in the rain the rust shows the extent of the cracks. One nearly crossed the main bearing oil passage.

 

[adf5565]

I'd love to get a 6.5 Optimizer but that's alot of coin to spend. Does anyone have a confirmed crack free block? Used motors aren't exactly cheap right now and most likely have the same crack issues that I have now so I feel like its playing the lottery spending $1k-2k for something that's probably in the same situation I'm in now. At least for the ones I've found sellers don't seem very receptive to pulling the oil pan and performing a thorough inspection prior to selling either.

The reason I asked about potential stopgap solutions is that these cracks have probably been present for a long time and it still runs fine so I am curious if there is an option that would help prevent the situation from getting worse. I'm not performing any other lower end work and not going to add any more money to this block so if one day something gives I'll invest in a better solution.

 

[87cr250r]

Yes, the option is to install Lock-N-Stitch inserts

Order # FFT5SP001K, FFT Style Special Application Inserts - Basic Kits On Lock-N-Stitch

Browse Order # FFT5SP001K, FFT Style Special Application Inserts - Basic Kits in the Lock-N-Stitch catalog including Item Name,Description,Shipping Weight,Metric,Inch,A,B,C,Tap,Order #,Inserts (Package of 5),Install Kit,Drill Bit,Kit Contents,Applica

castingrepair.locknstitch.com

Some recommend using 10mm Inserts and and replace the outer bolts with the 10mm bolts from a 2001+ engine. The cap remains the same.

 

[87cr250r]

Also, the crack is already full of oil. Just wipe the area dry and spray it with some talcum powder. That will show the crack just as well as dye pen.

 

[adf5565]

Yes, the option is to install Lock-N-Stitch inserts

Order # FFT5SP001K, FFT Style Special Application Inserts - Basic Kits On Lock-N-Stitch

Browse Order # FFT5SP001K, FFT Style Special Application Inserts - Basic Kits in the Lock-N-Stitch catalog including Item Name,Description,Shipping Weight,Metric,Inch,A,B,C,Tap,Order #,Inserts (Package of 5),Install Kit,Drill Bit,Kit Contents,Applica

castingrepair.locknstitch.com

Some recommend using 10mm Inserts and and replace the outer bolts with the 10mm bolts from a 2001+ engine. The cap remains the same.

Interesting, what would install be like for those?

 

[MarkM]

I've seen some of these stitching repairs and it is strong, permanent and frankly amazing what can be repaired but it is costly. A good block is relatively inexpensive and the issue is put to bed fast.

Mark

 

[adf5565]

I've seen some of these stitching repairs and it is strong, permanent and frankly amazing what can be repaired but it is costly. A good block is relatively inexpensive and the issue is put to bed fast.

Mark

Any ideas where to find a good block? The typical places I go to buy used parts would be an unknown on condition.

 

[MarkM]

I see you are in PA. I would look at https://tnjmurray.com/ . I've purchased numerous parts from them and they have always treated me right. They are located in Delaware.

Mark

 

[87cr250r]

Keep in mind that the Lock N Stitch kit for the 6.2/6.5 block does not involve metal stitching. The crack does not get repaired but is stabilized with the insert instead. Obviously the engine runs fine with the crack so there is no need to repair them. The labor to install the inserts is minimal. The trick is finding a shop with the kit as the kit itself is probably $400+. I've helicoiled main bearings on a 350 Chevy with a hand drill. If you're enterprising you can do this repair yourself with the engine in the truck. The bolts aren't aligning the main caps so they're pretty loose on their tolerances.

 

[nyoffroad]

Yes, the option is to install Lock-N-Stitch inserts

Order # FFT5SP001K, FFT Style Special Application Inserts - Basic Kits On Lock-N-Stitch

Browse Order # FFT5SP001K, FFT Style Special Application Inserts - Basic Kits in the Lock-N-Stitch catalog including Item Name,Description,Shipping Weight,Metric,Inch,A,B,C,Tap,Order #,Inserts (Package of 5),Install Kit,Drill Bit,Kit Contents,Applica

castingrepair.locknstitch.com

Some recommend using 10mm Inserts and and replace the outer bolts with the 10mm bolts from a 2001+ engine. The cap remains the same.

To me that kit looks like it's more of a thread repair (Heli-coil) kit. If your worried about the bolt getting ripped out of the block then that kit might work, as for repairing a crack, no.

 

[nyoffroad]

Any ideas where to find a good block? The typical places I go to buy used parts would be an unknown on condition.

Tioga Pa. can't be but a few hours away from CUCVRUS , check and see if he has any.

 

[adf5565]

So I ended up bringing this to resolution. If I did it over again i would’ve done it differently but such is life I guess. I initially went down the path of looking for a crack free block and did end up finding one. Only problem then was finding a place that had availability to rebuild it. I don’t have all of the tools/knowledge/time to currently do that on my own, and the places around me that I called all were back up towards the end of July, which I can’t be without the truck that long.

In hindsight I should’ve just kept the bottom of my block as is since I’m still going to rebuild the different block, but I decided to purchase and install the lock n stitch inserts as well as ARP studs in my current one as well. The process of install wasn’t terrible but still a pain and fairly costly especially when I think that ideally I’ll only be running this one until next winter.

I had a buddy machine me a drill plate and I got a drill bushing to help keep the drill straight, and essentially just drill out the hole, tap, and install the insert. These inserts are really cool, the thread design is such that instead of spreading a hole, the threads actually pull the material closer to the insert and are supposed to make it stronger than it was new.

Then installed the main studs and tightened everything to spec.

 

[87cr250r]

The only error you have made is that your repaired engine is probably going to out live the truck so you'll never get around to building that new one.